This invention relates to a torquing apparatus. More particularly, it relates to a torquing apparatus which is especially useful for torque wrenches and with which it is possible to deliver a series of torque inputs or loads without the need for and complications of a ratchet mechanism.
Many kinds of torque wrenches are known in the art, including manually operated wrenches and wrenches that are powered hydraulically or pneumatically. It is often desired that such wrenches be capable of delivering a sequential series of torque inputs or loads to a fastener without removing the wrench from the fastener and repositioning it each time. Such sequential operation requires some kind of ratchet mechanism (or similar mechanism) in order to recycle the wrench for each succeeding operating stroke while the wrench remains on the fastener being tightened.
While such wrenches (i.e., ratchet wrenches) are generally suitable for their intended purposes, they do have a number of problems or undesirable features. For example, the nose radius of the wrench around the output drive shaft is a critical limiting factor in determining accessability of the wrench to fasteners that are located in remote or closely confined places. Simply stated, if the nose of the wrench is bigger than the available space around the fastener, then the wrench can not be positioned to mount the output drive shaft on the fastener. In ratchet wrenches, the ratchet mechanism generally dictates the size of the nose radius of the wrench, so the ratchet becomes a limiting factor in determining the accessability of the wrench to closely confined places.
In prior art ratchet type wrenches, the ratchet also defines the minimum stroke of the wrench. As a result, it is not possible, at least with powered wrenches, to adjust the length of the stroke at the discretion of the operator of the wrench.
In ratchet type wrenches, it is often necessary to incorporate a "no back" feature to deal with the problem of the release of wound up torque in the fastener during the return stroke of the wrench. This release of wound up torque may present an operational problem in lost motion in the wrench which may prevent the ratchet from resetting.
Ratchet type wrenches are also inherently complicated by the complications of the ratchet mechanism; and the ratchet mechanism establishes the operational load limit of the wrench because all of the torque load must be transmitted through the ratchet mechanism. Also, the cost of the wrench is increased as the requirements for complexity and sophistication of the ratchet mechanism increase.